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Electrical conductivity of Cu-Ag in situ filamentary composites

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中国有色金属学会会刊：英文版 2007年第2期17卷 378-383页

作者：宁远涛张晓辉吴跃军 kunming institute of precious metals

The electrical conductivity of Cu-10Ag in situ filamentary composite was studied during the deformation and annealing processes. The dependence of electrical resistivity of the deformed composites on the true strain presents a two-stage change with increase of the true strain. The intermediate heat treatment and the stabilized annealing treatment to the deformed composite promote the separation of Ag precipitate, and increase the electrical conductivity. The maximum conductivity of the composite experienced the stabilizing heat treatment can reach about 97% IACS with σb≥400 MPa at 550 ℃ annealing, and reach about 70% IACS with σb≥1 250 MPa at 300 ℃ annealing. The corresponded strength of the composite was reported. The microstructure reason for the changes of the conductivity was discussed.

关键词： Cu-Ag合金丝状复合材料导电性显微结构

Partial phase diagram of Au-Ag-Dy ternary system

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中国有色金属学会会刊：英文版 2005年第4期15卷 738-742页

作者：张康侯陈江 kunming institute of precious metals

On the basis of Au-Ag, Au-Dy and Ag-Dy binary phase diagrams, the 700℃ isothermal section of Au-Ag-Dy ternary system（Dy≤35%, mole fraction） was established by X-ray diffraction analysis, differential thermal analysis and optical microscopy. It is found that there is a long single-phase region, Au（Ag） or Ag（Au）, along the Au-Ag binary isomorphous system on the gold-silver-rich side of the 700℃ isothermal section and between the binary compound Au2Dy and Ag2Dy there is the all proportional solid solution, （Au2Dy） or （Ag2Dy）. It is confirmed that the partial 700℃ isothermal section consists of six single-phase regions: solid solution Au（Ag） or Ag（Au）, （Au2Dy） or （Ag2Dy）, Au6Dy, Au51Dy14, Au3Dy and Ag51Dy14; nine binary-phase regions: （Au2Dy）+Au（Ag）, Au6Dy+Au（Ag）, Au（Ag）+Ag51Dy14, Ag51Dy14+（Au2Dy）, Au3Dy+（Au2Dy）, Au3Dy+Au51Dy14, Au51Dy14+Au6Dy, Au51Dy14+Au（Ag） and Au（Ag）+Au3Dy;four ternary regions: Ag51Dy14+（Au2Dy）+Au（Ag）, （Au2Dy）+Au（Ag）+Au3Dy, Au（Ag）+Au3Dy+Au51Dy14 and Au51Dy14+Au（Ag）+Au6Dy. No new ternary compound is formed in the gold-silver-rich field（Dy≤35%） of the Au-Ag-Dy ternary system.

关键词：金银镝三重系统等温线相平衡热力学合金相图

Influence of Cerium Addition on Microstructure and Properties of Cu-Ag Alloy in Situ Filamentary Composites

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Journal of Rare Earths 2005年第S1期23卷 392-398页

作者：宁远涛张晓辉秦国义 kunming institute of precious metals Kunming 650221 China

The in situ filamentary composites based on the Cu-10Ag and Cu-10Ag-Ce alloys were prepared. The microstructure and properties of the composites were studied. The effects of Ce addition on the microstructure as cast, including refining Cu grains and the Ag filaments, increasing the proportion of (Cu+Ag) eutectic and decreasing the proportion of the Ag precipitate, were researched. The average size of the Ag filaments in the composites could be approached by a formula: d=C·exp(-0.228η), here C is a coefficient related to the size of the original grains and 1500 nm for Cu-10Ag and 800 nm for Cu-10Ag-Ce. A two-stage strain strengthening effect was found for the deformed composites, that is the dislocation strengthening at low strain stage and the ultra-fine Ag filaments or interface strengthening at the high strain stage. The intermediate heat treatment at lower temperature further refined the Ag filaments and therefore improved the properties. The high strengthening rate of Ce addition on Cu-10Ag alloy attributed the refining effect to Cu grains and Ag filaments. The typical properties of the heavy deformed composites with 1 IHT reached to UTS=1500 MPa with conductivity 62% IACS for the Cu-10Ag alloy and UTS=1550 MPa with conductivity 65% IACS for the Cu-10Ag-Ce alloy, respectively.

关键词： composite Cu-Ag alloy Ce addition microstructure strength conductivity

Photochemical synthesis of bimetallic Au-Ag nanoparticles with “core-shell” type structure by seed mediated catalytic growth

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中国有色金属学会会刊：英文版 2005年第2期15卷 310-313页

作者：董守安唐春 institute of precious metals Kunming 650221 China

The colloidal Au core/Ag shell structure composite nanoparticles were synthesized in PEG-acetone solution by photochemical route. The monodispersed Au nanoparticles with average diameter of 3.9 nm were used as growth seeds. The optical property of colloids and the sizes of composite nanoparticles were characterized when the molar ratio of Au to Ag ranges from 4∶1 to 1∶4. The results show that a composite nanoparticle structure similar to strawberry shape is formed at the molar ratio of Au to Ag from 4∶1 to 1∶1; the composite nanoparticles consisting of a core of Au and shell of Ag were generated at the 1∶4 molar ratio, having a striking feature of forming (interconnected) network structure.

关键词：金-银胶质光化学合成核-壳结构纳米合金材料

Experiment and finite element method analysis mass erosion and transfer of Ag/La_2NiO_4-based electrical contacts during operation

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Rare metals 2013年第1期32卷 93-99页

作者： Song Chen Wei-Ming Guan Kun-Hua Zhang Zhi-Long Tan Ming Xie kunming institute of precious metals State Key Laboratory of Advanced Technologies for Comprehensive Utilization of Platinum metals

A uniform transient temperature field model of electrical contacts operation was found by analyzing the process of closing arc constriction resistance Joule heat ~ breaking arc. Essential parameters of Ag/La2NiO4 electrical contact material for transient temperature field calculation were obtained through tests of electrical contact experimental instrument under 18 V DC in different cur- rents, other correlation experiments, and calculation anal- ysis. The finite element method was applied to solve the transient temperature field, and the features and distribution of the transient temperature field were obtained. The condition of material erosion and mass transfer can be forecasted by those calculation results. It is beneficial to research about the lifetime of Ag/La2NiO4 electrical material.

关键词： Electrical contact Finite element Mass transfer Erosion Temperature field model

EFFECT OF Y ON THE SPINODAL DECOMPOSITION RATE AND MECHANICAL PROPERTIES OF Cu-9Ni-6Sn ALLOY

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Transactions of Nonferrous metals Society of China 1992年第4期2卷 78-81页

作者： Deng Zhongmin kunming institute of precious metals Kunming 650221China

By measurement of mechanical and electrical properties,modulation wavelength,TEM techniques,etc.,the effect of Y on the spinodal decomposition in a Cu-9Ni-6Sn alloy has been *** results show that Y can accelerate spinodal decomposition in the alloy,hinder the growth of celluoid structurers occurring at grain boundaries,and improve the combination of strength and plasticity.

关键词： Cu-9Ni-6Sn spinodal decomposition Y

FACTORS INFLUENCING SOLID SOLUBILITIES OFRARE-EARTHS IN Pd

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维普期刊数据库

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Acta Metallurgica Sinica(English Letters) 1997年第4期10卷 318-322页

作者： YN Ning and YT. Ning(kunming institute of precious metals, kunming 650221, China) kunming Inst of precious metals Kunming China

A parameter describing the solid solubilities of mre-earths in Pd, Nf/aX(TR - rPd),was proposed, where N is the fshell filled electron nutnben △X the electronegativity dtherence between Palladium and rare-earths, rR the atotnic radii of rare-earth elementand rPd of Pd. The marimum solid solubilities are linear relation to this parnmeterexcept La, Nd and Ce.

关键词： solid solubility rare-earth palladiutn

METASTABLE PHASES IN RAPIDLY-SOLIDIFIED ALUMINIUMRICH Al-Sm ALLOYS

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Acta Metallurgica Sinica(English Letters) 1998年第4期11卷 301-306页

作者： Y.T.Ning (institute of precious metals, kunming 650221, China) Inst of precious metals Kunming China

The splat foils of Al-Sm alloys with 0.04-0.06mm in thickness were made by hammeranvil technique. The estimated cooling rute was 106K/ order of magnitude. The extended solid solubility of Sm in α-Al reached 0.5at. % Sm. The intermediate phase in the rapidlysolidified Al-Sm alloys is Al11Sm3 phase, which is stable only at temperatures above 1339K in equilibrium state and retained to ambient temperature as a metastable phase, whereas the equlibrium intermediate phase, Al3Sm, was restricted to occur.

关键词： Al-Sm alloy rapid solidification metastable phase

XRD STUDY OF RECOVERY PROCESS OF COLD DEFORMED Ag AND Ag-Ce ALLOY

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Acta Metallurgica Sinica(English Letters) 1996年第1期9卷 27-31页

作者： NING Yuantao WENFei(kunming institute of precious metals kunming 650221.China) kunming Inst of precious metals Kunming China

The recovery processes of cold deformed Ag and Ag-Ce alloy containing trace cerium were studied by XRD *** on Scherrer formula and an analytical program,the lattice distortion and subgrain size for both Ag and Ag-Ce alloy were determined in the recovery *** cold deformed high purity Ag showed tow recrystallization temperature,obvious lattice relaxation and *** trace Ce solute is an effective inhibitor for recovery softening of high purity Ag since it raises the recrystallization temperature and restrains the lattice relaxation.

关键词： Ag Ag-Ce alloy recovery microalloying